CN114101127A

CN114101127A - Robot solar panel cleaning system

Info

Publication number: CN114101127A
Application number: CN202111213885.XA
Authority: CN
Inventors: A.M.阿尔-奥泰比
Original assignee: Saudi Arabian Oil Co
Current assignee: Saudi Arabian Oil Co
Priority date: 2017-08-04
Filing date: 2018-08-06
Publication date: 2022-03-01
Also published as: CN110945297B; SG11202000320WA; SA520411094B1; US10771008B2; CN110945297A; EP3662211B1; WO2019028459A1; EP3896362A1; EP3662211A1; KR20200037316A; US20200366235A1; SG10202112217UA; US20190044476A1; JP2020530249A; US11489487B2

Abstract

A cleaning system (100) for a solar panel (115) is provided. The cleaning system (100) comprises: i) a frame (105) movable in a lateral direction over the solar panel (115) and having edges oriented in the lateral direction; a brush assembly (110) positioned within the frame (105) and movable in a longitudinal direction and comprising a plurality of brush holders (182, 184) arranged within the frame (105), wherein each brush holder (182, 184) is adapted to interchangeably receive a brush for cleaning the solar panel (115); and a liquid spray device comprising spray nozzles (122, 124) arranged in one or more rows for spraying at least one of water and a water detergent compound onto the solar panel (115). The liquid spray assembly includes a nozzle positioned near at least one of the lateral edges of the frame for spraying an aqueous cleaning compound onto the longitudinal ends of the brush assembly.

Description

Robot solar panel cleaning system

The application is a divisional application of an invention patent application with the application date of 2018, 8 and 6, and the application number of 201880047776.5, and the name of the invention is a robot solar panel cleaning system.

Technical Field

The present invention relates to the generation of electrical energy by using photovoltaic solar panels, and in particular to a system for cleaning solar panels to increase their efficiency.

Background

Renewable energy sources, including solar energy, are becoming an increasingly large part of the global energy structure. Most solar energy capture is performed using photovoltaic solar cell panels. The panels are typically covered with a transparent glass cover for protecting the solar cells from direct exposure to the environment. However, over time, glass covers can accumulate dirt, organics, sand, mud, fungal growth, and other debris, which reduces the power generation efficiency of the solar panels they cover. Examples of build-up on the panel cover are shown in fig. 1 and 2. Fig. 1 shows a solar panel covered over most of its surface with a scattered layer of dirt (such as dust) or sand. Figure 2 shows another solar panel whose surface is covered with streaks of residue with significant accumulation near the edges of the panel. The residue as shown in fig. 2 tends to adhere to the solar panel cover and can be difficult to remove. Various studies have shown that dirt accumulation can reduce solar panel output power by up to 80%. Furthermore, it has been found that small particles have a particularly detrimental effect on the power output. For example, covett records a 17% reduction in power of solar panels due to sand accumulation after six days.

Conventional methods and systems employed to date for cleaning and maintaining solar panels are often disqualified in terms of cleaning efficiency, certain times to clean accumulations are better than others, lack durability, or suffer from other obstacles, such as high demand for water, which may be undesirable in environments where water is difficult to obtain (e.g., deserts).

It would therefore be advantageous to provide a solar panel cleaning system that is efficient, requires a small amount of water, and is adaptable and durable. The present disclosure addresses these and other deficiencies in the art.

Disclosure of Invention

Embodiments of the present invention provide a cleaning system for solar panels. The cleaning system comprises: i) a frame movable in a lateral direction over the solar panel, the frame having lateral edges oriented in the lateral direction; ii) a brush assembly positioned within the frame and movable in the longitudinal direction, the brush assembly comprising a plurality of brush holders arranged within the frame, wherein each brush holder is adapted to interchangeably receive a brush for cleaning a solar panel; and iii) a liquid spray device comprising spray nozzles arranged in at least one row for spraying at least one of water and a water detergent compound onto the solar panel. The liquid spray assembly includes a nozzle positioned adjacent at least one of the lateral edges of the frame for spraying at least one of water and a water detergent compound onto the longitudinal ends of the brush assembly.

In some embodiments, the liquid-ejection device includes a plurality of rows of nozzles positioned within the frame, the rows of nozzles oriented in a lateral direction.

The cleaning system of the present invention may further comprise a forced air device for applying forced air to the solar panel. In some embodiments, the forced air device comprises a plurality of nozzles oriented to apply pressurized air to the solar panel. In other embodiments, the forced air device comprises a plurality of fans located at respective longitudinal positions within the frame. A combination of nozzles and fans may also be used.

Embodiments of the cleaning system additionally include a support bar for movably supporting the frame as the frame moves over the solar panel. The cleaning system may include a pulley system adapted to drive the frame relative to the support bar. In some embodiments, a separate power source may be used to power the cleaning system, which is active when the solar panel(s) itself is not operating.

The cleaning system according to the invention may further comprise a second pulley system for moving the brush holder in the brush assembly relative to the frame. The second pulley system drives the brush holder in the longitudinal direction.

A further embodiment of the cleaning system comprises a first sensor for determining the position of the frame relative to the support bar and a control unit coupled to the sensor and configured to reverse the lateral direction of travel of the frame when it receives data from the sensor indicating that the frame has reached a position limit past the solar panel.

Some embodiments include a second sensor for determining an amount of water available to the cleaning system. In such embodiments, the control unit may be coupled to the second sensor and configured to reduce usage of the liquid ejection device upon receiving data indicative of low water availability. The control unit may also be coupled to a diagnostic module that provides efficiency data for the solar panel. The control unit may be configured to activate or deactivate at least one of the liquid spraying device or the forced air device in dependence on the received efficiency data.

Embodiments of the invention also include a method of cleaning a solar panel, the method comprising: i) providing a brush assembly comprising a plurality of brush holders adapted to receive interchangeable brushes, wherein the brush assembly is incorporated in a frame; ii) moving the frame with the brush assembly over the surface of the solar panel while the brush is in contact with the surface of the solar panel; iii) moving the brush relative to the frame within the brush assembly; and iv) spraying the water cleaner mixture onto the solar panel to remove debris and onto the brush assembly to clean the brush.

In some embodiments, the cleaning method additionally includes applying forced air onto the solar panel to further clean debris from the solar panel.

In some embodiments, the water detergent mixture is sprayed from at least one row of nozzles oriented along the direction of motion of the frame.

In further embodiments, the cleaning method further comprises receiving information about the power generation efficiency of the solar panel; and controlling the spraying of the water cleaner mixture and the application of forced air onto the solar panel based on the received information about the power generation efficiency of the solar panel. In some embodiments, the method further comprises controlling movement of the frame based on the received information about the power generation efficiency of the solar panel. In a further embodiment, the frame is detected when it has reached a limit of position in its movement over the solar panel, and if the limit has been reached, the direction of movement of the frame is reversed. In addition, a water level available for cleaning the solar panel may be detected, and the injection of the water detergent mixture onto the solar panel may be controlled based on the detected available water level.

Any combination of the various embodiments and implementations disclosed herein may be used.

These and other aspects, features and advantages will be apparent from the following description of certain embodiments and drawings of the invention and from the claims.

Drawings

FIG. 1 is a perspective view of an example solar panel covered with scattered debris.

Fig. 2 is a perspective view of an example solar panel covered with a residue film.

Fig. 3 is a schematic top view of an embodiment of a solar panel cleaning system according to an embodiment of the present invention.

FIG. 4 is an enlarged view of the cleaning system shown in FIG. 3 with the underlying solar panel removed.

Fig. 5 is a schematic top view of a frame and brush assembly of a solar panel cleaning system according to an embodiment of the present invention.

FIG. 6 is a schematic top view of an embodiment of a forced air and liquid injection system for removing contaminants from a solar panel according to the present invention.

FIG. 7 is a schematic top view of an alternative embodiment of a forced air system for removing contaminants from a solar panel employing a fan in accordance with the present invention.

Fig. 8 is a schematic block diagram of an exemplary embodiment of a control system for operating a cleaning system according to the present invention.

It is noted that the drawings are illustrative and are not necessarily drawn to scale.

Detailed Description

By way of overview, the present disclosure describes an online cleaning system that cleans and maintains solar panels under efficient conditions while the solar panels are operational. The cleaning system includes an adjustable frame and replaceable cleaning elements, and is therefore adaptable to different sizes and arrangements of solar panels.

Figure 3 is a schematic top view of a cleaning system according to an embodiment of the present invention. The cleaning system 100 includes a rectangular frame 105 that is elongated along one dimension (represented as a longitudinal axis). The frame 105 has a first longitudinal end 107 and a second longitudinal end 109 and surrounds the brush assembly 110. The first end 107 is movably coupled to a first support bar 112 and the second end 109 is movably coupled to a second support bar 114. The frame 105 is movable in a forward and rearward direction along the

support rods

112, 114 in an orientation denoted as a transverse axis. A motorized pulley system or similar power mechanism (not shown in fig. 3) is used to power the movement of the frame along the

support rods

112, 114. The frame 105 is shown mounted above the solar panel 115. The surface area of the solar panels is typically in the range of 0.5 to 2 square meters and is covered with a transparent protective cover made of glass. The length of the frame 105 is adjusted to approximately match the length of the panel 115. The solar panel 115 may be a single panel, but in most solar power plants will be part of a row of similar panels ("solar row") that extends further along the transverse axis. The support bars 112, 114 may extend along the entire solar row and, when this is the case, the frame 105 may be moved along the support bars 112, 114 to cover the entire solar row. A first row of spray nozzles 122 coupled to the support bar 112 or located near the support bar 112 is positioned to direct a spray stream of cleaning fluid toward the brush assembly 110 proximate the first end 107 of the frame. A second row of spray nozzles 124 coupled to or located near the support bar 114 is positioned to direct a spray stream of cleaning fluid toward the brush assembly 110 proximate the second end 109 of the frame. A power supply 130 positioned above the frame 105 provides power to the cleaning system 100 and may also be part of the power supply system that powers other modules of the solar panel installation. The power supply 130 may be an additional dedicated solar cell dedicated to providing power to the cleaning system. Alternatively, the power source 130 may be implemented as a rechargeable power source. For example, the power source 130 may include a rechargeable battery that may be charged by one or more solar panels when the panels are operating, and then the cleaning system may utilize the energy stored by the battery when the panels are offline.

FIG. 4 is an enlarged view of the cleaning system shown in FIG. 3 with the underlying solar panel removed. As shown, the frame 105 is coupled to a first set of wheels 160 at the first end 107 and a second set of wheels 162 at the second end 109. The wheel sets 160, 162 enable the frame 105 to slide horizontally (along a lateral axis) into contact with rails, flanges, or similar traction surfaces on the support bars 112, 114. In the depicted embodiment, the wheel sets 160, 162 are mounted to rotate in the plane of the frame 105 and solar panel (i.e., the rotational axis of the wheels is perpendicular to the plane of the frame and solar panel). In other embodiments, the wheel sets may be mounted and oriented perpendicular to or otherwise from the orientation shown in FIG. 4.

In one embodiment of the drive mechanism, a motor (not shown) activates the drive pulley 160, which drive pulley 160 in turn activates the first and second step pulleys 162, 164. The step pulley 162 drives a step chain 165 on the support bar 112, and the step pulley 164 drives a step chain 167 on the support bar 114. This mechanism moves the wheels on the support rods, which in turn pulls the frame 105 across the solar panel in a forward and rearward direction. The first direction switch 170 is connected to the drive pulley 160 and is operable to cause the drive pulley to drive the step pulleys 162, 164 in the forward direction, and the second direction switch 172 is also connected to the drive pulley and is operable to cause the drive pulley to drive the step pulleys 162, 164 in the rearward direction. The direction switch may be activated by an operator command or automatically using a control unit based on a device detecting the position of the frame 105. In some embodiments, limit sensors and/or encoders may be employed to determine the position of the frame relative to the

support rods

112, 114. The control unit may use the signal from the detector to determine whether the frame has completely passed the length of the solar panel and, if so, to reverse the direction of movement of the frame.

Fig. 5 is a schematic top view of the frame 105 and brush assembly 110 according to an embodiment of the present invention. The brush assembly 110 is enclosed within the frame 105, the brush assembly 110 including a set of brush holders (e.g., 182, 184) arranged in longitudinal rows along a substantial length of the frame. Each

brush holder

182, 184 is configured to receive an interchangeable brush (not expressly shown). The brushes are modular and adapted to fit onto the

brush holders

182, 184 by snap-fit, tongue-and-groove, sleeve, and other suitable coupling methods. In this manner, a variety of different types of brushes, such as soft microfiber, sponge, and Roper brushes, may be interchangeably incorporated into the brush assembly 110 in different orders and locations. The brush assembly 110 is adapted to be moved in its entirety in a longitudinal direction (perpendicular to the movement of the frame itself) by a mechanism such as a pulley 190 and a chain 192. In some embodiments, the pulley 190 may be driven by the same drive pulley 150 of the moving frame 105 through an intermediate transmission. Other brush drive mechanisms may also be used. In the embodiment of fig. 5, the

brush holders

182, 184 are coupled directly to the chain 192. When the chain 190 is moved by the pulley 190, the brush holder is carried in the longitudinal direction. The chain 190 may be a conveyor belt that moves the brushes in a continuous loop such that each brush moves continuously and periodically to the end of the cleaning tunnel. The brush cleans the solar panel while moving along the frame. When the brush reaches the edge of the frame, it is cleaned by exposure to a powerful jet of water/detergent mixture from a row of fluid jet nozzles 122 (in fig. 3) positioned on or near the support bar. In some embodiments, the direction of movement of the brush assembly may be unidirectional, while in other embodiments, a reversing mechanism is employed for bi-directional movement.

In fig. 6 a schematic top view of an embodiment of an air/liquid jet system 200 for a cleaning system according to the invention is shown. The system 200 includes a forced air ventilation or blowing device ("forced air device") for assisting in removing and moving the dust particles in front of the frame. The system 200 further comprises a liquid jet device 215, said liquid jet device 215 being adapted to supply a water-detergent mixture for similar cleaning purposes. In one embodiment, the forced air device includes a first set of air nozzles 212 arranged in a column adjacent a first outer longitudinal edge of the frame 105, and a second set of air nozzles 214 arranged in a column on another outer longitudinal edge of the frame 105. Although not shown in fig. 6, both sets of nozzles 212, 214 are coupled to the frame 105 and extend from the frame 105. The air nozzle sets 212, 214 are also in fluid communication with a source of forced air that may be distributed along the frame 105. In the depicted embodiment, the liquid-ejection device includes five rows of

nozzles

221, 222, 223, 224, and 225 oriented horizontally along a transverse axis inside the frame 105. A fewer or greater number of nozzle rows (with a different number of nozzles in each row) may be used. The nozzle rows 221-225 preferably spray a water/cleaner mixture at a high pressure sufficient to cover and remove dirt and debris. It should be noted that the volume of fluid used in the spray can be kept to a minimum if and when required, such as in a dry environment, in order to conserve water resources. The liquid spray device communicates with a water and detergent supply line (not shown) which may also supply the brush cleaning nozzle 122 shown in fig. 2.

In an alternative embodiment of the forced air device shown in fig. 7,

fans

232, 234, 236 distributed longitudinally within the frame direct forced air towards the solar panel. When operating, power for operating the

fans

232, 234, 236 may be provided by a solar panel or solar bank.

In another alternative embodiment, the liquid-ejection device may comprise a stand-alone system, such as "shower-head" sprayers distributed over the solar panel. In one embodiment, a water supply conduit having holes facing the solar panels may be installed along the upper end of the solar row. As the liquid flows through the conduit, the liquid is projected through the apertures in the manner of a spray head onto the solar panel surface. In addition, air and liquid supply lines providing forced air and water/detergent for cleaning may be placed on the rollers moved by the step chain to follow the path of the frame. As shown in fig. 7 and as previously noted, the

dedicated spray nozzles

252, 254 are positioned to clean the brushes in the brush assembly as they reach the end of each cleaning stroke through the frame.

Fig. 8 is a high-level block diagram of an embodiment of a control system 800 for operating a solar panel cleaning system in accordance with the present invention. The control unit 802, which may be implemented as one or more processors and/or Programming Logic Units (PLUs) and cache memories, is operable to generate commands for operating and receiving data from other devices of the system 800. The control unit 802 generates commands automatically or in response to user (operator) commands 804 received manually or via a remote device such as a smartphone. The control unit receives sensory input from a number of devices and communicates commands to a plurality of actuator devices to operate the cleaning system.

The sensor device includes a limit sensor or encoder 806 that detects the relative position of the frame with respect to the support bar (and the solar panel), and may also detect whether the frame has reached a preset limit in its direction of movement with respect to the solar panel. A water level sensor 808 is connected to the water supply line and measures the amount of water available to clean the system. The water level sensor 808 may be a static meter for measuring the water level in the reservoir or the flow in the supply line, or may be an active component in communication with other parts of the larger water supply system. The control unit 802 also receives solar power generation efficiency data of the solar panel from the diagnostic module 809.

The actuator device operated by the control unit 802 includes a frame movement control 810 for moving the frame over the solar panel. As described above, the frame movement control 810 includes one or more actuators for operating motors, pulleys, chains, direction switches, and/or other components that control movement of the frame in the forward and reverse directions. The air nozzle/fan control 812 includes actuators operable to, for example, open and close nozzles of an air nozzle system and/or activate or deactivate one or more fan elements. Similarly, the liquid-ejection control 814 includes an actuator operable to open and close a nozzle of the liquid-ejection system. The brush assembly movement control 816 includes an actuator for operating the pulley and chain that moves the brushes longitudinally within the frame of the cleaning system.

In operation, when the limit sensor/encoder 806 detects that the frame has completed traversing the solar panel (or row) in either the forward or reverse direction, this information is received by the control unit 802, which can activate the direction switch to change the direction of movement of the frame. Similarly, when the water level sensor 808 detects a low water level below a certain threshold and sends this information to the control unit 802, the control unit 802 may reduce the amount of water used in the spray during cleaning operations, reduce the frequency of cleaning operations, or stop operation altogether until the water availability improves.

In addition, by controlling the air/fluid injection system, the control unit 802 may vary the amount and frequency of air applied, for example, based on ambient conditions and information about the efficiency of the solar panel. When it is determined that the panel is covered with a large amount of debris, the air flow may be increased by activating (e.g., turning on) the air nozzle and/or increasing fan operation. Similarly, the control unit 802 may increase the amount of fluid jet applied to the solar panel and the amount of detergent applied in the water/detergent mixture by controlling the spray nozzles of the liquid spray device. Conversely, when the panel is relatively clean, the control unit 802 may reduce the amount of air flow and fluid jets by turning off one or more nozzles and/or reducing fan operation of the forced air device.

The cleaning system disclosed herein has many advantages in terms of increased efficiency and reduced cost. Since the brushes of the cleaning system are modular and replaceable, maintenance can be easily performed and new brushes can be made to periodically replace older brushes, which become less efficient. Furthermore, the interchangeability of the brushes enables the choice of the type of brush that is best suited to the prevailing conditions at the time of installation. In addition, the use of forced air helps to prevent mechanical damage to the panel surface due to dislodging dust accumulations.

It is to be understood that any structural and functional details disclosed herein are not to be interpreted as limiting the system and method, but are instead provided as representative embodiments and/or arrangements teaching one skilled in the art one or more ways to implement the method.

It should be further understood that throughout the several drawings, like numerals indicate like elements and that not all of the components and/or steps described and illustrated with reference to the drawings are required for all embodiments or arrangements

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The directional terminology used herein is used for purposes of convention and reference only and is not to be construed as limiting. However, it should be recognized that these terms may be used with reference to a viewer. No limitation is therefore implied or inferred.

Also, the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having," "containing," "involving," and variations thereof herein, is meant to encompass the items listed thereafter and equivalents thereof as well as additional items.

While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications will be appreciated by those skilled in the art to adapt a particular instrument, situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A method of cleaning a solar panel, the method comprising:

providing a frame movable in a lateral direction over the solar panel, the frame having lateral edges oriented in the lateral direction;

providing a brush assembly positioned within the frame, the brush assembly comprising a plurality of brush holders arranged within the frame, the brush holders being movable in a longitudinal direction within the brush assembly, each brush holder being adapted to receive an interchangeable brush for cleaning the solar panel, incorporating the brush assembly in the frame;

providing a liquid ejection device, the liquid ejection device comprising:

a plurality of rows of nozzles positioned within the frame and oriented in the transverse direction, the plurality of rows of nozzles configured to spray at least one of water and a water cleaner mixture onto a solar panel; and

at least one further row of nozzles adjacent to at least one of the lateral edges of the frame, the at least one further row of nozzles positioned such that when each of the plurality of brush holders moves in the longitudinal direction and reaches an end of the frame positioned proximate to the at least one lateral edge of the frame, the nozzles in the at least one further row of nozzles are configured to spray at least one of water and a water cleaner mixture onto each of the plurality of brush holders positioned proximate to the lateral edge of the frame to directly clean the brush or solar panel;

moving the frame with the brush assembly over a surface of the solar panel while the brush is in contact with the surface of the solar panel;

moving the brush relative to the frame within the brush assembly; and

a water cleaner mixture is sprayed onto the solar panel to remove debris and onto the brush assembly to clean the brush.

2. The method of claim 1, further comprising applying forced air to the solar panel to further clean debris from the solar panel.

3. The method of claim 1, wherein the aqueous detergent mixture is sprayed from at least one row of nozzles oriented along a direction of movement of the frame.

4. The method of claim 2, further comprising:

receiving information about the power generation efficiency of the solar panel; and

controlling the spraying of the water cleaner mixture and the application of forced air onto the solar panel based on the received information about the power generation efficiency of the solar panel.

5. The method of claim 4, further comprising:

controlling movement of the frame based on the received information regarding the power generation efficiency of the solar panel.

6. The method of claim 1, further comprising:

detecting whether the frame has reached a positional limit in its movement over the solar panel; and is

If the limit has been reached, the direction of movement of the frame is reversed.

7. The method of claim 1, further comprising:

detecting a water level available for cleaning the solar panel; and

controlling the spraying of the water detergent mixture onto the solar panel based on the detected available water level.